Forecast Tool Could Predict Winter Months Ahead


Could we have seen this brutal winter coming?

Groundhogs aside, meteorologists historically haven’t been able to say how severe a winter may get very far in advance. But climate scientists have a new modeling tool that may be able to more reliably predict the severity of winter weather months ahead -- giving residents of the Atlantic coasts plenty of time to stock up on rock salt.

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Climate models perform poorly when it comes to long-term seasonal forecasts in higher latitudes because slowly changing drivers of the climate system, such as the ocean, don’t affect higher latitude air circulation in the same way as the tropics, limiting meteorologists’ ability to predict events such as North Atlantic winter storminess very far in advance.

But a fundamental component of the North Atlantic climate may prove the key to extending meteorologists’ lead time from weeks to months, writes a team from the Met Office Hadley Centre, a climate research institute in Exeter, U.K. The team focused on predicting the North Atlantic Oscillation (NAO), an annual variation in air pressure over the Atlantic Ocean. The NAO shapes the path of the Atlantic jet stream, which in turn affects winds and storms throughout the North Atlantic.

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The team found that their high-resolution climate model could predict the fluctuations of the NAO up to four months in advance, and validated the model’s predictive power using historical weather data. Further, their model turned out robust forecasts for winter air temperature, wind speed, and the frequency of winter storms in the Atlantic, the team writes in Geophysical Research Letters, which published their results.

Although further experiments will identify the reason behind the model’s predictive power, the team thinks that a connection between El Niño/La Niña patterns in the Pacific and the NAO, which is represented in their model, may play a part.

PHOTOS: NASA's TERRA satellite captures a winter wonderland in New England following a February 2007 storm. Credit: NASA

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